/*
 * Tencent is pleased to support the open source community by making BK-CI 蓝鲸持续集成平台 available.
 *
 * Copyright (C) 2020 THL A29 Limited, a Tencent company.  All rights reserved.
 *
 * BK-CI 蓝鲸持续集成平台 is licensed under the MIT license.
 *
 * A copy of the MIT License is included in this file.
 *
 *
 * Terms of the MIT License:
 * ---------------------------------------------------
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.tencent.bkrepo.common.artifact.stream

import java.io.InputStream
import kotlin.math.min

/**
 * 限定长度的输入流
 * @param delegate 实际操作的输入流
 * @param limit 限制读取的长度
 */
class BoundedInputStream(
    delegate: InputStream,
    limit: Long
) : DelegateInputStream(delegate) {

    private var pos: Long = 0
    private val length: Long = limit
    private var isPropagateClose: Boolean = true

    init {
        require(length >= 0) { "Limit value must greater than 0." }
    }

    override fun read(): Int {
        if (pos >= length) {
            return EOF
        }
        val result = super.read()
        pos++
        return result
    }

    override fun read(byteArray: ByteArray): Int {
        return this.read(byteArray, 0, byteArray.size)
    }

    override fun read(byteArray: ByteArray, off: Int, len: Int): Int {
        if (pos >= length) {
            return EOF
        }
        val maxRead = min(len.toLong(), length - pos).toInt()
        val bytesRead = super.read(byteArray, off, maxRead)
        if (bytesRead != EOF) {
            pos += bytesRead
        }
        return bytesRead
    }

    override fun skip(n: Long): Long {
        val toSkip = min(n, (length - pos))
        val skippedBytes = super.skip(toSkip)
        pos += skippedBytes
        return skippedBytes
    }

    override fun available(): Int {
        return (length - pos).toInt()
    }

    override fun close() {
        if (isPropagateClose) {
            super.close()
        }
    }

    @Synchronized
    override fun reset() {
        super.reset()
    }

    @Synchronized
    override fun mark(readlimit: Int) {
        super.mark(readlimit)
    }
}
